In steam generating apparatuses, such as boilers and concentration cans, the metal in contact with steam and condensed water may corrode due to feed water-containing oxygen and components of M-alkalinity. Regarding to condenser systems in particular, carbon dioxide generated together with steam in boilers and the like dissolves again in water at condensation of steam, leading to the decrease in pH of condensed water (condensation), which frequently causes severe corrosion of pipes and devices. As the methods to prevent such corrosion, there has been conventionally carried out the chemical process with strong basic-type amines such as morpholine and long-chain aliphatic amines such as octadecyl amine, besides the processes of ion exchange and degassing for the objective to degass carbonate in feed water.
In case that the steam generated in boilers is to be used for food processing and the production process of pharmaceutical agents and for humidification of air conditioning of buildings, a high degree of hygienic safety is required for steam. Some of the amine-type chemical agents described above have received approval for their use as the additives for boilers from U.S. FDA Standards, but the objectives of the utility of generated steam have been limited and the concentration of the agents in steam also has limitation. Additionally, they are not necessarily satisfactory in terms of safety. Hence, even in the case that some concerns about the corrosion of pipes and devices of steam and condenser systems may be present, steam is used without chemical processing, in order to ensure safety.